JP3686602B2 - Work vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a work vehicle.
[0002]
[Prior art]
Conventionally, there is a work vehicle in which the left and right traveling devices have different traveling drive speeds to make the aircraft turn, and in order to change the traveling speed, the speed ratio can be changed in a forward / reverse stepless manner with a shift lever or the like. For continuously turning, use a continuously variable transmission for turning that can change the gear ratio between forward and reverse continuously by a steering wheel, etc., and the output of these continuously variable transmissions is a left and right planetary gear mechanism. The left and right traveling parts are individually driven.
[0003]
[Problems to be solved by the invention]
As described above, since two expensive continuously variable transmissions are used, there is a problem that the manufacturing cost becomes high.
[0004]
In addition, when the vehicle is moving backward, the relationship between the direction of operation of the steering wheel and the turning direction of the airframe is opposite to that when moving forward and is different from the wheel type work vehicle.
[0005]
[Means for Solving the Problems]
Therefore, in the present invention, in a work vehicle in which the vehicle body turns by varying the traveling speed of the left and right traveling devices, the left and right planetary gear mechanisms are connected to the engine via a forward / reverse clutch and a linear power transmission system, while being linked to the engine. The rotation speed of the continuously variable transmission for turning and the continuously variable transmission for turning that can be connected and operated by operating the steering wheel and the rotational speed of the continuously variable transmission for turning to the rotational speeds in the forward and reverse directions with the same absolute value. It is linked to the left and right planetary gear mechanisms via a turning power transmission system consisting of forward and reverse rotation division mechanisms that divide and output, and the left and right planetary gear mechanisms synthesize the straight power transmission system and the rotational speed from the turning power transmission system, respectively. The left and right traveling devices are individually driven at these combined rotational speeds, and the power from the engine is exclusively selected by the forward / reverse clutch and arranged on the lower side thereof. And a turning power transmission system for turning a continuously variable transmission, with branches in the main transmission section of the rectilinear drive train consisting of a gear transmission mechanism to be transmitted, Mu for pivoting of the pivotal movement force transmission system A step transmission is installed outside the mission case, and its input shaft and output shaft are interlocked and connected to a linear power transmission system consisting of a gear-type transmission mechanism inside the mission case. It is to provide.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the present invention is as follows.
[0007]
That is, the work vehicle according to the present invention is configured such that the input side of the forward / reverse clutch is interlocked with the engine and the output side of the forward / backward clutch is interlocked with the gear-type transmission mechanism to form a linear power transmission system. The output side of the power transmission system is linked to the left and right sun gears of the left and right planetary gear mechanisms, while the turning continuously variable transmission is linked to the engine, and the forward / reverse rotation division mechanism is linked to the turning continuously variable transmission. Thus, the turning power transmission system is configured, and the rotational power in the forward and reverse bi-directional directions with the same absolute value output by the forward / reverse rotation splitting mechanism is input to the left and right ring gears of the left and right planetary gear mechanisms, respectively. The gear mechanism is configured to synthesize the rotational speeds from the straight power transmission system and the turning power transmission system, respectively, and by changing the output rotational speed of the continuously variable transmission for turning by operating the steering wheel, It is configured to perform turning by different travel drive speed.
[0008]
Here, the turning continuously variable transmission is disposed on the lower side of the forward / reverse clutch, and the rotation direction of the input shaft of the turning continuously variable transmission is switched in conjunction with the switching operation of the forward / reverse clutch. So that.
[0009]
【Example】
Embodiments of the present invention will be described with reference to the drawings.
[0010]
FIG. 1 shows a work vehicle according to the present invention. The tractor A includes a driving unit 3, a motor unit 4 and the like above a traveling unit 2 equipped with a crawler-type left and right traveling devices 1a and 1b. The vehicle body frame 5 is mounted, and a rotary tiller 6 as an agricultural machine is connected to the rear end portion of the vehicle body frame 5.
[0011]
As shown in FIGS. 1 to 3, the traveling unit 2 is arranged by extending a pair of left and right vertical frames 7a and 7b in the front-rear direction, and the front and rear portions of the left and right vertical frames 7a and 7b are A traveling part frame 9 is constituted by connecting front and rear gate-type frames 8a and 8b having expanded lower openings, and the front ends of the left and right vertical frames 7a and 7b are respectively connected via tensioners 10. The left and right front idler wheels 11a and 11b are pivotally supported, and the left and right rear idler wheels 12a and 12b are pivotally supported at the rear ends of the left and right vertical frames 7a and 7b, respectively. A plurality of rolling wheels 13 are pivotally supported, and left and right sprockets 14a and 14b are pivotally supported above the left and right vertical frames 7a and 7b, respectively. The left and right sprockets 14a and 14b - La 15a, left and right traveling devices 1a by winding 15b, constitutes a 1b.
[0012]
In particular, in this embodiment, the front and rear gate frames 8a and 8b are used to connect the left and right vertical frames 7a and 7b, and the minimum ground clearance is increased to improve the traveling performance in the field. Further, since the work implement is connected to the rear of the work vehicle A, the front idler wheel 11 is mounted at a higher position than the foremost wheel 13 and is attached to the front ends of the left and right crawlers 15a and 15b. The angle of attack α of about 21 degrees is formed to improve the running performance when oversteps such as kites.
[0013]
As shown in FIGS. 1 to 3, the vehicle body frame 5 is constructed by extending left and right side members 16a, 16b in the front-rear direction on the upper surfaces of the front and rear portal frames 8a, 8b. The front and rear struts 17a and 17b are erected at the front and rear ends of 16b, respectively, and the round pipe is refracted to form an upper frame that is inclined in a substantially U-shape in the rear opening in a plan view and inclined to the front, rear, and rear height in a side view. A frame 18 is formed, and the upper frame 18 is installed on the upper ends of the front and rear columns 17a and 17b to form a frame-shaped vehicle body frame 5.
[0014]
A steering wheel 21 is erected at the front end of the vehicle body frame 5, and a seat 22 is arranged behind the steering wheel 21 at a predetermined interval to constitute the driving unit 3. An engine 23 is disposed in the engine 23, and a transmission 24 is disposed below the engine 23 to constitute the prime mover unit 4. The left and right sprockets 14a and 14b are left and right drive shafts 25a and 25b projecting left and right from the transmission 24. Are respectively fitted to the outer ends of the. In the figure, 26 is a vehicle body cover, 27 is a battery, 28 is a fuel tank, and 29 is a shift lever.
[0015]
In particular, the seat 22 where the driver is seated and the weight is greatly increased, and the engine 23 and the transmission 24 that are heavy are connected to the inner upper side of the ground contact surface WB, that is, the foremost wheel 13 and the rear idler of the traveling unit 2. Arranged above the wheel 12, the work vehicle A has a good front-rear weight balance and improves the stability of the vehicle body against the front-rear tilt.
[0016]
In addition, heavy objects such as a 27 battery and a fuel tank 28 are also disposed above the foremost wheel 13 and the rear idler wheel 12 to enhance the stability of the vehicle body against the forward and backward inclination.
[0017]
The rotary tiller 6 is connected via a three-point link mechanism 30 provided at the rear part of the vehicle body frame 5, and the lifting hydraulic pressure interposed between the vehicle frame 5 and the top link 31. The rotary tiller 6 is moved up and down by a cylinder 32, and the power from the engine 23 is transferred from the engine 23 to the rotary tiller 35 via the work machine drive shaft 33 and the belt transmission mechanism 34. To communicate.
[0018]
FIG. 4 shows another embodiment in which the operation unit 3 and the engine 23 are disposed in the same position as described above, but the transmission 24 is disposed below the seat 22. The tensioner 10 of the traveling unit 2 is shown in FIG. It differs from the previous embodiment in that it is disposed behind the left and right vertical frames 7a and 7b to pivotally support the rear idler wheel 12 and pivotally support the front idler wheel 11 via a bracket 36.
[0019]
Also in this embodiment, heavy objects such as the seat 22, the engine 23, the transmission 24, the battery 27, and the fuel tank 28 are disposed on the inner upper side of the ground surface WB to enhance the stability.
[0020]
5 to 8 show a first embodiment of the transmission 24. The first to ninth shafts 41 to 49 are supported in parallel inside the mission case 40, and the middle portion of the first shaft 41 is shown. The input side of the forward clutch 50a, and the input side of the forward and backward clutches 50a and 50b loosely fitted in the middle of the second shaft 42 via the first meshing gear 51 with the input side of the first shaft 41, The output shaft of the forward clutch 50a and the second shaft 42, which is the output side of the reverse clutch 50b, are connected to the third shaft 43 through the second meshing gear 53. The power transmission of the forward / reverse clutches 50a and 50b can be exclusively selected to enable forward / reverse switching in the driving direction.
[0021]
The third shaft 43 is linked to an input shaft 55 of a turning continuously variable transmission (hereinafter referred to as HST) 54 and is connected to an input shaft 55 of a main transmission 57 through a third meshing gear 56. 44, the turning continuously variable transmission 54 is arranged on the lower side of the forward / reverse clutches 50a, 50b, and in conjunction with the switching operation of the forward / reverse clutches 50a, 50b, The rotation direction of the input shaft of the transmission 54 is switched.
[0022]
A slider 60 integrally formed with dogs 58, 58 at both ends and a second speed driving gear 59 at the center is fitted to the fourth shaft 44 so as to be axially slidable and non-rotatable. Between the four shafts 44 and the fifth shaft 45 that is the output shaft of the main transmission 57, always-meshing first and third speed meshing gears 61 and 62 are interposed, and the fifth shaft 45 is slidable. The second speed passive gear 63 is fitted, and the output rotational speed of the main transmission unit 57 can be switched in three stages by sliding the slider 60.
[0023]
A sub-transmission unit 64 is connected to the main transmission unit 57 in series. The sub-transmission unit 64 is interposed between the fifth shaft 45 and the sixth shaft 46 that is the output shaft of the sub-transmission unit 64. The output rotational speed of the sub-transmission unit 64 is sandwiched between the neutral position by sliding the slider 67 that is interposed between the high and low speed meshing gears 65 and 66 and is fitted to the sixth shaft 46 so as to be axially slidable and non-rotatable. The speed can be changed in two stages, high and low.
[0024]
In this way, the forward / reverse clutches 50a, 50b, the three-speed shift main transmission 57 and the two-speed shift sub-shift 64 are linked in series. Six stages of shifting operations are possible.
[0025]
The sixth shaft 46 is interlocked and connected to the seventh shaft 47 via a chain interlocking mechanism 68, and left and right sun gears 69 a and 69 b fitted to the left and right ends of the seventh shaft 47, respectively, Left and right cages 70a, 70b connected to left and right drive shafts 25a, 25b arranged with the same axis line, and a plurality of left and right planetary gears 71a, 71b respectively attached to the left and right cages 70a, 70b, The left and right planetary gear mechanisms 74a and 74b are constituted by the left and right ring gears 73a and 73b interlocked and connected to the output shaft 72 of the HST 54. The rotational power transmitted to the left and right sun gears 69a and 69b by the straight power transmission system M composed of the mechanical gear type transmission mechanism and the left and right rebounds from the HST 54 of the turning power transmission system H described later. The rotational power transmitted to the gears 73a and 73b is combined, and the combined rotational power is fitted to the left and right drive shafts 25a and 25b via the left and right planetary gears 71a and 71b and the left and right cages 70a and 70b. Each of the left and right sprockets 14a and 14b is individually transmitted.
[0026]
The output shaft 72 of the HST 54 is provided with a forward / reverse rotation division mechanism 75 that transmits the rotation speed of the output shaft 72 to the left and right ring gears 73a and 73b in a complementary manner. The eighth shaft 48 is linked to the output shaft 72 of the HST 54 via the reduction gear group 76, and the eighth shaft 48 is linked to the ninth shaft 49 via the first intermediate meshing gear 77. 49, left and right output gears 78a and 78b are fitted to the left and right ends, respectively, and the left output gear 78a and the left ring gear 73a are interlocked and connected via two idle gears 79 and 79 arranged in series. The output gear 78b and the right ring gear 73b are interlocked and connected through one idle gear 79, and the absolute value of the rotational speed is the same, but the left ring gear 73a rotates in the same direction as the ninth shaft 49, The ring gear 73b has a ninth And so as to transmit the rotation in the opposite direction to the 49.
[0027]
Then, one end of the first shaft 41 as an input shaft of the transmission 24 is projected from the side surface of the mission case 40, and the projecting end and the engine output shaft 80 are interlocked and connected via the belt mechanism 34. The steering wheel 21 is interlocked and connected to the speed change operation unit 104 (see FIG. 11) of the HST 54, and the speed ratio of the HST 54 is changed in a forward and reverse stepless manner according to the turning operation of the steering wheel 21.
5, 81 is a rotary shaft, 82 is a tilling claw, 83 and 84 are chain transmission mechanisms, 85 a and 85 b are shifters of the forward / reverse clutches 50 a and 50 b, and 87 is a sub-transmission unit 64. A shifter 88 is a meshing bevel gear for taking out power to the outside.
[0028]
With this configuration, the power from the engine 23 is shifted in six stages in the front-rear direction and transmitted to the left and right traveling devices 1a and 1b of the traveling unit, and the output rotation speed of the HST 54 is changed according to the operation angle of the steering wheel 21, The driving speed of the traveling devices 1a and 1b can be varied to turn the work vehicle A in the direction in which the driving speed has decreased.
[0029]
In particular, in this embodiment, since the input shaft 55 of the HST 54 is linked to the output side of the forward / reverse clutch 50b, the HST 54 can be switched simultaneously with the switching of the forward / reverse clutches 50a and 50b without operating the steering wheel 21. The output rotation direction of the vehicle is switched, and the operation direction of the steering wheel 21 and the turning direction of the work vehicle A maintain a certain relationship, and the turning operation is performed with substantially the same feeling as the steering operation of the wheel type vehicle. be able to.
[0030]
FIG. 9 shows a second embodiment of the transmission 24. In this embodiment, the input shaft 55 of the HST 54 is interlocked with the engine 23 without using the forward / reverse clutches 50a and 50b. Instead, a forward / reverse switching mechanism 90 is provided between the eighth shaft 48 and the ninth shaft 49, and a switching operation between the forward / reverse switching mechanism 90 and the forward / reverse clutches 50a, 50b is performed. The operation direction of the steering wheel 21 and the turning direction of the work vehicle A are maintained in a fixed relationship by switching the rotation direction of the power transmitted to the left and right ring gears 73a and 73b in conjunction with each other.
[0031]
That is, the first shaft 41 and the input shaft 55 of the HST 54 are interlocked and connected via the first meshing gear 91, and left and right driving gears 92a and 92b are fitted to the left and right sides of the eighth shaft 48, respectively. The gear 92a and the left passive gear 93a loosely fitted to the ninth shaft 49 are interlocked and connected via two idle gears 79, 79 arranged in series, and the right prime mover gear 92b and the right passively fitted to the 49th are connected. A passive gear 93b is interlocked and connected through one idle gear 79, and a slider 94 having dogs 58 and 58 formed on the left and right ends respectively on the ninth shaft 49 is slidable in the axial direction and not rotatable. The rotation direction of the power transmitted to the left and right sun gears 69a and 69b is switched by sliding the slider 94, and the rest is substantially the same as the first embodiment.
[0032]
FIG. 10 shows the relationship between the operating angle of the steering wheel 21, that is, the output rotation speed of the HST 54, and the driving speeds of the left and right traveling apparatuses 1a and 1b. The horizontal axis indicates the output rotation speed of the HST 54. Each solid line indicates the driving speed at the first speed to the sixth speed of one of the crawler type traveling devices from the bottom, and each broken line indicates the other from the bottom to the other. The driving speed at the first speed to the sixth speed of the crawler type traveling apparatus is shown, and the lower hatched portion h indicates that the driving speed of the slower crawler type traveling apparatus is from zero to the traveling speed of the aircraft. The range until the transition to the opposite direction is shown, and the size of the arrow in the lower frame indicates the driving speed of the left and right traveling devices 1a and 1b.
[0033]
In this embodiment, even if the relationship between the operation angle of the steering wheel 21 and the gear ratio of the HST 54 is limited and the steering wheel 21 is rotated to the maximum operation angle θ1, the third speed to the sixth speed. In traveling, the sign of the vector of the traveling drive speed of the left traveling apparatus 1a is the same as the sign of the vector of the traveling drive speed of the right traveling apparatus 1b, and the pivot turn and the spin turn cannot be performed. Yes, in the second speed traveling, the slower crawler traveling device becomes zero and the pivot turn is possible but the spin turn cannot be performed. In the first speed traveling, the left traveling device The sign of the driving drive speed vector of 1a and the sign of the driving drive speed vector of the right traveling device 1b can be made different to enable pivot turning or spin turning, and the steering wheel 21 can be operated at the maximum steering angle. When rotated to θ2 which is about 1/2 of θ1, in the 2nd to 6th speed travel, the sign of the travel drive speed vector of the left travel apparatus 1a and the travel drive speed vector of the right travel apparatus 1b In the first speed running, the slower crawler running device becomes zero and the pivot turn is possible, but the spin turn is possible. Is not allowed.
[0034]
Thus, at the time of high speed traveling from the third speed to the sixth speed, positive / negative turning driving of the turning power transmission system H for the left and right traveling apparatuses 1a, 1b when the steering wheel 21 is turned to the maximum. Since the travel drive speed vector of the straight power transmission system M is set to be larger than the maximum speed vector, sudden turning is prevented, safety during turning is ensured, and the first for work etc. When traveling at a low speed at the first or second speed, the work efficiency can be improved by performing a pivot turn or a spin turn.
[0035]
FIG. 11 shows a hydraulic circuit. The discharge side of the lifting hydraulic pump 52 is connected to the hydraulic circuit inside the HST 54, and the lifting hydraulic pump 52 is also used as the charge pump of the HST 54. In the figure, 100 is a hydraulic valve for raising and lowering control, 101 is a relief valve, 102 and 103 are hydraulic pumps and hydraulic motors inside the HST 54, 104 is a speed change operating unit, 105 is a check valve, and 106 is a throttle valve.
[0036]
【The invention's effect】
According to the present invention, the following effects can be obtained.
[0037]
That is, in the present invention, the left and right planetary gear mechanisms are connected to the engine via a forward / reverse clutch and a straight power transmission system, while the engine is linked to the engine and the output rotation speed can be changed by operating the steering wheel. Via a turning power transmission system comprising a continuously variable transmission for rotation and a forward / reverse rotation dividing mechanism for dividing and outputting the output rotational speed of the continuously variable transmission for turning into two rotational speeds of the same normal and reverse directions. It is linked to the left and right planetary gear mechanism, and the left and right planetary gear mechanism combines the linear power transmission system and the rotational speed from the turning power transmission system, respectively, and the left and right traveling devices are individually driven at these combined rotational speeds. The power from the engine is exclusively selected by the forward / reverse clutch, and is a linear power consisting of a continuously variable transmission for turning of the turning power transmission system disposed on the lower side and a gear-type transmission mechanism. Together to be branched and transmitted to the main transmission section of reach system, turning power transmission system for turning a continuously variable transmission is mission Ke - by So設to scan outside the mission the input shaft and the output shaft The work vehicle is interlocked and connected to a linear power transmission system composed of a gear-type transmission mechanism inside the case.
[0038]
In this way, only one expensive continuously variable transmission is required, the structure can be simplified, and the manufacturing cost can be reduced.
[0039]
In addition, the power from the engine is exclusively selected by the forward / reverse clutch, and the main power of the linear power transmission system comprising the continuously variable transmission for the turning power transmission system and the gear-type transmission mechanism arranged on the lower side thereof. Since it is branched and transmitted to the transmission unit, the structure is simplified and the operation direction of the steering wheel and the turning direction of the airframe can be maintained in a fixed relationship regardless of the forward and backward movement of the airframe. The steering wheel can be operated with the same feeling as a wheel-type work vehicle, the operation during turning can be facilitated, and the operational safety can be ensured satisfactorily.
[0040]
Here, since the rectilinear power transmission system is composed of a gear-type transmission mechanism, the rectilinear power transmission system can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is a side view of a work vehicle according to the present invention.
FIG. 2 is a plan view of a traveling unit.
FIG. 3 is a front view of a traveling unit.
FIG. 4 is a side view of a working vehicle according to another embodiment.
FIG. 5 is a power transmission system diagram (first embodiment).
FIG. 6 is a sectional side view of a transmission (first embodiment).
FIG. 7 is a cross-sectional plan view of a transmission showing a straight power transmission system (first embodiment).
FIG. 8 is a cross-sectional plan view of a transmission showing a turning power transmission system (first embodiment).
FIG. 9 is a power transmission system diagram (second embodiment).
FIG. 10 is a graph showing the relationship between the driving speed of the left and right traveling device and the HST output rotation speed.
FIG. 11 is a hydraulic circuit.
[Explanation of symbols]
A Work vehicle H Turning power transmission system M Straight traveling power transmission system 1a, 1b Left and right traveling device 21 Steering wheel 23 Engine 50a, 50b Forward / reverse clutch 54 Turning continuously variable transmission 55 Input shaft 74a, 74b Left and right planetary gear mechanism 75 Forward / reverse Rotation division mechanism

Claims (1)

In a work vehicle (A) in which the vehicle body turns by varying the traveling speeds of the left and right traveling devices (1a, 1b), the engine (23) is connected to a forward / reverse clutch (50a, 50b) and a straight power transmission system (M). The left and right planetary gear mechanisms (74a, 74b) are connected to the engine (23), and the output continuously changing speed can be changed by operating the steering wheel (21) (54). ), And a turning power transmission system (75) that divides the output rotational speed of the continuously variable transmission (54) into forward and reverse two-direction rotational speeds having the same absolute value. H) is coupled to the left and right planetary gear mechanisms (74a, 74b) through the left and right planetary gear mechanisms (74a, 74b), and the rotation speed from the straight power transmission system (M) and the rotational power transmission system (H) is determined. The left and right traveling devices (1 1b), and the power from the engine (23) is exclusively selected by the forward / reverse clutches (50a, 50b) and is arranged on the lower side of the turning power transmission system (H) The stepless transmission (54) for turning and the main transmission (57) of the linear power transmission system (M) composed of a gear-type transmission mechanism are branched and transmitted , and the turning power transmission system ( H ), the continuously variable transmission for turning ( 54 ) is installed outside the mission case ( 40 ) , and its input shaft ( 55 ) and output shaft ( 72 ) are gears inside the mission case ( 40 ). A work vehicle characterized in that it is linked to a straight-ahead power transmission system ( M ) consisting of a transmission mechanism .

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